1. Field
The subject matter disclosed herein relates to electronic devices, and more particularly to methods, apparatuses and articles of manufacture for use in affecting a motion model within a mobile device based, at least in part, on one or more determined range rates for one or more wireless signals acquired from one or more terrestrial transmitters.
2. Information
The Global Positioning System (GPS) represents one type of Global Navigation Satellite System (GNSS), which along with other types of satellite positioning systems (SPS) provide or otherwise support signal-based position location capabilities (e.g., navigation functions) in mobile devices, and particularly in outdoor environments. However, since some satellite signals may not be reliably received and/or acquired by a mobile device within a specific environment, different techniques may be employed to enable position location services.
For example, mobile devices may attempt to obtain a position fix by measuring ranges to one or more terrestrial transmitters (e.g., wireless access point devices, beacons, cell towers, etc.) which are positioned at particular locations. Such ranges may be measured, for example, by obtaining a MAC ID address or some other transmitter identifier from signals received from such transmitters and obtaining range measurements to the transmitters by measuring one or more characteristics of signals received from such transmitters such as, for example, signal strength, a round trip time delay, etc.
In addition to satellite position systems and specific positioning systems, existing wireless carrier infrastructures may enable observed time difference of arrival (OTDOA) and/or advanced forward link trilateration (AFLT) techniques for estimating the locations of mobile devices. Here, with knowledge of the locations of neighboring base station transmitters and time-reference data, a mobile station may measure a range to such base station transmitters based upon an observed signal propagation delay (e.g., by comparing a phase of an acquired signal to a time reference).
As pointed out above, certain navigation techniques and/or AFLT techniques typically involve measuring ranges to transmitters at known fixed locations. As such, movement of a mobile device may be detected if there is a measurable difference or change in range to a fixed-location transmitter over time. In extreme multipath environments, however, measurements of changes in range using certain navigation and/or AFLT techniques may not be reliable for measuring small changes in position that would indicate smaller movements.